Articulated mats are used for offshore coastal and marine applications where separation, stabilization, protection and scour prevention is needed for pipelines and other underwater installations. These mats are particularly useful in areas where considerable hydrodynamic forces are generated by bottom currents and waves. Thus, for example, a seabed pipeline can be covered with such a mat so that the pipeline is stabilized by the weight of the mat. Another benefit of the mat is its ability to prevent erosion of the adjoining seabed. Examples of articulated mats, their components, and their uses are given in European patent specification 0152232, and U.S. Pat. Nos. 2,876,628; 2,674,856; 4,370,075; 4,357,928; 4,417,828; 5,052,859; and 5,193,937.
A problem with use of mats is the placement of the mats on the seabed pipeline to be protected. Prior art handling and deployment frames require diver intervention and are difficult to obtain accurate placement. Prior art devices have required the use of multiple releasing aligning guides, which tangle in subsea usage. Multiple shackles or operating hydraulic valve controls prior to the mat being properly deployed have been created, but these result in the slow release of the mat on the seabed floor and expensive procedures and may involve pollution of the environment.
There is, therefore, a need in the art for a seabed mat placement system that can be easily released with low force applied to the release mechanism to activate it. There is also a need in the art for subsea mat placement systems that do not have a potential for environment pollution, such as by leaving parts, such as ropes on the seabed floor. There is a further need for a seabed mat placement system that can be quickly released and will accurately place the mat in deep water with high accuracy.